To determine the functional response of 5-HT1A in unmedicated schizo- phrenics, major depressive patients (Bipolar and unipolar) manic patients and obsessive compulsive patients by examining hormone responses following oral administration of ipsapirone and to determine if the hormone effects of ipsapirone are modified by chronic treatment with antidepressants (fluoxetine, imipramine), lithium carbonate or antipsychotic drugs (clozapine, haloperidol, etc.).